Coastal Wetlands Highly Vulnerable to Sea-Level Rise

Submitted by Susmita Dasgupta
On Thu, 02/28/2013

Sea-level rise from climate change is a serious global threat, and there is overwhelming scientific evidence that sea-level will continue to rise for centuries even if green house gas concentrations were to be stabilized today.

Recently, Brian Blankespoor, Benoit Laplante and I investigated potential impacts of sea-level rise on coastal wetlands. Our study[1] indicates a rise in sea levels due to climate change of just one meter could destroy more than 60 percent of the developing world’s coastal wetlands currently found at one meter or less elevation. We estimate that such a rise would lead to economic losses of around $630 million per year.

In our analysis, we looked at various types of coastal wetlands at risk in 76 countries and territories, using a number of databases and satellite maps. According to the data, about 99 percent of the coastal wetlands at elevations of one meter or less in the Middle East and North Africa could disappear, as well as 77 percent in sub-Saharan Africa, 66 percent in East Asia and 39 percent in Latin America and the Caribbean.

Our estimates further indicate that most of the damages would be concentrated in a few countries in East Asia, the Middle East and North Africa. For example, about three-quarters of coastal fresh-water marshes that would be affected by the one-meter rise in sea levels worldwide are located in five countries: Argentina, China, Iran, Mexico and Vietnam. Similarly, 61 percent of saline wetlands at risk are in Egypt and Libya.

In recent years, coastal wetlands have been disappearing more quickly than other ecosystems, mainly because of land development. Sea-level rise from climate change will exacerbate these losses, leading to wetlands being submerged, pushed inland, or blanketed with salt. How those wetlands fare will vary, depending on the slopes and water flows in the surrounding area.

These findings are alarming, because wetlands don’t exist just for the birds and plants – people rely on them for water, food, transportation, and other essential goods and services. We hope our research can motivate steps to protect wetlands, especially since global warming will, for sure, accelerate the rise of sea levels.

The resulting economic losses from coastal wetland destruction will be in addition to other coastal impacts such as the forced relocation of people and infrastructure. An earlier World Bank study [2]predicted that 60 million people in developing countries would be forced out of their homes if sea levels rise by one meter.

The wetlands study comes as World Bank President Jim Yong Kim is urging the global community to take action on climate change.

(My thanks to Jane Zhang and Michael Toman for their valuable contribution to the post.)